Zigbee 3.0 is winning the IoT’s low-power mesh market

By Cees Links, GM of Qorvo Wireless Connectivity Business Unit

As the Internet of Things (IoT) market accelerates and becomes more of a reality, the hype surrounding it becomes more intense and more confusing. It is time for a reality check, to take inventory of which IoT wireless standards are succeeding today and which are designed to survive and thrive in the future. A major force paving the path for the wireless future — the collective experience of more than 400 companies gathered and refined over 15 years — has now resulted in a technology “hardened for use” by consumers and in the industry: Zigbee 3.0.

Having spent most of my career pioneering the wireless data industry — and having led the team that created and popularized Wi-Fi, I’ve seen firsthand the trials and tribulations of wireless standards. Two years ago, for instance, IoT innovators heavily discussed and debated different radio technologies that would be useful for the IoT. Some companies advocated that Wi-Fi and Bluetooth would be sufficient, while other companies advocated for IEEE 802.15.4 (the underlying radio technology for Zigbee and Thread).

Radio variations gaining little market traction
The Wi-Fi and Bluetooth advocates created variations on their preferred radio technology in order to gain the upper hand in the market. In early 2016, for instance, the Wi-Fi Alliance introduced a new initiative for low-power Wi-Fi (IEEE 802.11ah) to address a key weakness of Wi-Fi as compared to the others — a relatively high energy demand. Although efforts in this area have proceeded and led to a standard, it is now clear that worldwide acceptance of IEEE 802.11ah is doubtful. Major regions around the globe will require different versions of the same standard, creating a very complex environment for adoption. Adding to this challenge is the fact that, even though this new low-power standard is called Wi-Fi, it is not compatible with traditional Wi-Fi. It is a completely new and different radio and MAC technology. Thus, this new flavor of “Wi-Fi” does not make much sense.

Likewise, Bluetooth, as an IoT standard, has a critical weakness. It was designed as a point-to-point cable replacement technology, not a networking technology. To address this mismatch, companies started to work on a network layer for Bluetooth, called “Bluetooth Mesh,” but they have faced serious challenges. Indeed, many industry networking engineers have previously seen similar mesh networking attempts fail. For example, IEEE 802.11s exists but is hardly used and implements only a single hop mesh topology (repeater). The key problem is that latency cannot be controlled when supporting multiple hops. So the skepticism among network technology engineers around the new Bluetooth Mesh story is really no surprise.

Today, most of today’s networking technology decision makers fully understand that the IoT will use all three radio technologies, matching the best technology to the IoT’s range of applications, and realize that the worldwide wireless market has accepted all three core IoT radio technologies. IEEE/802.11/Wi-Fi, as we are all familiar with today, is preferred for content distribution; IEEE 802.15.4/Zigbee is used for sensor networks like smart homes; and Bluetooth, including Bluetooth Low Energy for connectivity, personal area networks (around the smartphone), and wearables. Zigbee and Wi-Fi connect devices in your home to the internet through a router or hub, whereas Bluetooth mainly uses the smartphone for its internet connection.

With so many different application types and needs, the IoT market has found that it needs all three major wireless technologies: Wi-Fi, Bluetooth, and Zigbee.

With this acceptance has come a variety of crossover radio products now available from multiple suppliers. Wi-Fi/Bluetooth, Zigbee/Bluetooth, and Wi-Fi/Zigbee/Bluetooth combinations are becoming widespread. They all may not be at the right price point yet, but the underlying message is clear: There are three large, open, worldwide, uniform radio communication standards that are now the cornerstones for the IoT. That is the good news.

But who will win the networking “standards wars”?

Now comes the not-so-good news — in the form of some new confusion above the radio layer. Over a decade ago, after the competing radio technology conflicts ended with Wi-Fi becoming the winner (and HomeRF and several other technologies disappearing), a new technology war erupted around the networking and application layers. Today, everyone is familiar with TCP/IP, and even if you have never heard of this technology, you are using it to communicate via the web and local networks. But to get to this stage, a battle was fought between multiple networking standards: Novell Netware (anyone remember that?), Banyan Vines, Microsoft LAN Manager, IBM SNA, and others. In those days, it was as if almost every large electronics company felt that they had to make their own personal imprint on history by defining a network layer technology.

That is essentially what is repeating today in the IoT and smart home spaces. Apparently, many of our industry-leading companies have not learned the lesson that standards wars harm and slow down the adoption of new technologies. Apple HomeKit, Google Thread/Brillo, Qualcomm Alljoyn, Intel IoTivity, and, more recently, China’s Huawei LiteOS are all emerging application frameworks now competing to get industry mindshare and to become the “leader in the IoT,” expecting the world to follow suit. Several use the same radio, but they still cannot intercommunicate.

But there is hope. Zigbee 3.0 (and its application layer, Dotdot ), have the capability of working together with each of these applications frameworks — so it will be interesting to see how this all evolves from closed and separated ecosystems into useful open and integrated end-user solutions because from a technology perspective, Zigbee 3.0 can support them all. Furthermore, it can do so reliably.

Zigbee 3.0 outshines the others
Zigbee has clearly become the technology of choice for many of the world’s IoT and smart home system makers by offering powerful ease-of-use features and strong security protocols. (Security protocols are a major challenge to implement in such systems because sensors and edge devices usually do not have keyboards with which to enter security codes.) Furthermore, with Zigbee 3.0, the Zigbee Alliance has reached a high level of maturity that includes a solid certification program addressing both network and application areas, an ecosystem of test houses, and more than 2,400 certified Zigbee product types. On top of that, Zigbee 3.0’s application library, Dotdot, has itself lived through multiple iterations of maturation. Therefore, it is no surprise that the Thread Group adopted this Zigbee Dotdot application library to run over Thread.

And there is more: Zigbee 3.0 also includes Zigbee Green Power. Zigbee Green Power was originally developed as an ultra-low-power wireless standard to support energy-harvesting devices, which are devices without batteries that can extract their energy requirement from the environment (e.g., motion, light, piezo, Peltier, etc.). The most common application of energy harvesting is the light switch, wherein the flipping of the switch generates the energy needed to send a communication package (“on,” “off,” etc.) through the air and to a lamp. Green Power is especially effective for devices that are only sometimes on the network (i.e., when they have power), enabling these devices to go on and off the network securely, so they can be off most of the time.

As an ultra-low wireless technology, Green Power is also a very effective option when using battery-powered devices because it enables them to run off of a battery for years. In addition, Green Power allows for low-cost end nodes to communicate with the rest of the network, specifically in situations in which there is no meshing required. All in all, Green Power is a terrific addition to Zigbee 3.0.

Wide compatibility is the key
Another advantage for Zigbee 3.0 is its internet compatibility. Zigbee devices, just like Wi-Fi devices, are usually connected to the internet via a router, gateway, or set-top box and, as such, can be immediately controlled by any other device that is connected to the internet — from PC to tablet or smartphone app and from any place in the world. Because Zigbee is fully Wi-Fi- and IP-compatible, there is no need to have a Zigbee chip in the PC, tablet, or smartphone itself to find and control Zigbee-connected smart home and IoT devices. It all happens through any web-connected hub (Zigbee-enabled router, set-top box, or gateway). This means that connected PCs and smartphones (via Wi-Fi or cellular) can function as dashboards because they can find and communicate with any Zigbee devices without a problem. Zigbee 3.0 is thus fully interoperable with existing internet applications.

As a result, Zigbee 3.0 is gaining steam in the IoT market. It is already supported by large-volume shipments. Estimates for devices using Zigbee technologies today range from 1 million units per week to 1 million units per day, which means that close to 1 billion Zigbee devices are already in the market. Zigbee is also the only standard wherein meshing has been implemented from the ground up. Therefore, the latency that is normally induced by the storing and forwarding of packages is minimal, contrary to standards in which meshing is added as an afterthought like in Bluetooth Mesh, where the point-to-point connectivity technology had meshing capability added on top.

Zigbee 3.0 is thus becoming the optimal solution for a wide range of smart home and industrial applications, including lighting, security, thermostats, remote controls, and more. It is secure and supports battery-free devices, meshing, low latency, and energy harvesting. It is unmatched and even unchallenged. Indeed, for many application builders, Zigbee 3.0 is the one and only networking solution that they will use on top of the IEEE 802.15.4 radio technology.

Zigbee 3.0 will be the low-power Wi-Fi for many of our future IoT sense-and-control networks and applications as well. And with an established roster of noteworthy companies and experts working behind the scenes through the Zigbee Alliance, there’s a lot more from the IoT solutions side that will come forth from this proven group of technologists.